Reference page — cumulative record through Monday, October 19, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.

CVE-2020-1967

CVE-2020-1967HIGH

OpenSSL OpenSSL — Segmentation fault in SSL_check_chain

  AV  AC  PR  UI  S  C  I  A   CVSS    EPSS   %ile   KEV
   N   L   N   N  U  N  N  H    7.5   .5334   99.0     —

AFFECTED
  Product  Versions                                            Fixed
  OpenSSL  Fixed in OpenSSL 1.1.1g (Affected 1.1.1d-1.1.1f) –  —

TIMELINE
  Dec 3   Reserved by openssl
  Apr 21  Published (CNA: openssl)
  Oct 8   ENRICHED — CVE-2020-1967 (OpenSSL). Received CVSS 7.5 and CPE data from NVD.
  Oct 8   EXPLOIT PUBLISHED — CVE-2020-1967 (OpenSSL). Public exploit reference added.

CWE-476 · CNA: openssl · CVSS v3.1 · 32 references · NVD status: Modified

Description

Server or client applications that call the SSL_check_chain() function during or after a TLS 1.3 handshake may crash due to a NULL pointer dereference as a result of incorrect handling of the "signature_algorithms_cert" TLS extension. The crash occurs if an invalid or unrecognised signature algorithm is received from the peer. This could be exploited by a malicious peer in a Denial of Service attack. OpenSSL version 1.1.1d, 1.1.1e, and 1.1.1f are affected by this issue. This issue did not affect OpenSSL versions prior to 1.1.1d. Fixed in OpenSSL 1.1.1g (Affected 1.1.1d-1.1.1f).

Lifecycle

Complete event history — 4 events, chronological
Date	Event	Detail
December 3, 2019	Reserved	Reserved by openssl
April 21, 2020	Published	Published (CNA: openssl)
October 8, 2026	ENRICHED	ENRICHED — CVE-2020-1967 (OpenSSL). Received CVSS 7.5 and CPE data from NVD.
October 8, 2026	EXPLOIT PUBLISHED	EXPLOIT PUBLISHED — CVE-2020-1967 (OpenSSL). Public exploit reference added.

Affected

Affected products and packages — 1 row
Vendor	Product / Package	Ecosystem	Version introduced	Fixed
OpenSSL	OpenSSL	—	Fixed in OpenSSL 1.1.1g (Affected 1.1.1d-1.1.1f)	—

Weaknesses

CWE-476

References (32)

http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00004.html [Mailing List, Third Party Advisory]
http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00011.html [Mailing List, Third Party Advisory]
http://packetstormsecurity.com/files/157527/OpenSSL-signature_algorithms_cert-Denial-Of-Service.html [Third Party Advisory, VDB Entry]
http://seclists.org/fulldisclosure/2020/May/5 [Mailing List, Third Party Advisory]
http://www.openwall.com/lists/oss-security/2020/04/22/2 [Mailing List, Third Party Advisory]
https://git.openssl.org/gitweb/?p=openssl.git%3Ba=commitdiff%3Bh=eb563247aef3e83dda7679c43f9649270462e5b1
https://github.com/irsl/CVE-2020-1967 [Exploit, Third Party Advisory]
https://kb.pulsesecure.net/articles/Pulse_Security_Advisories/SA44440 [Third Party Advisory]
https://lists.apache.org/thread.html/r66ea9c436da150683432db5fbc8beb8ae01886c6459ac30c2cea7345%40%3Cdev.tomcat.apache.org%3E
https://lists.apache.org/thread.html/r94d6ac3f010a38fccf4f432b12180a13fa1cf303559bd805648c9064%40%3Cdev.tomcat.apache.org%3E
https://lists.apache.org/thread.html/r9a41e304992ce6aec6585a87842b4f2e692604f5c892c37e3b0587ee%40%3Cdev.tomcat.apache.org%3E
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/DDHOAATPWJCXRNFMJ2SASDBBNU5RJONY/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/EXDDAOWSAIEFQNBHWYE6PPYFV4QXGMCD/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/XVEP3LAK4JSPRXFO4QF4GG2IVXADV3SO/
https://security.FreeBSD.org/advisories/FreeBSD-SA-20:11.openssl.asc [Patch, Third Party Advisory]
https://security.gentoo.org/glsa/202004-10 [Third Party Advisory]
https://security.netapp.com/advisory/ntap-20200424-0003/ [Third Party Advisory]
https://security.netapp.com/advisory/ntap-20200717-0004/ [Third Party Advisory]
https://www.debian.org/security/2020/dsa-4661 [Third Party Advisory]
https://www.openssl.org/news/secadv/20200421.txt [Vendor Advisory]
https://www.oracle.com//security-alerts/cpujul2021.html [Patch, Third Party Advisory]
https://www.oracle.com/security-alerts/cpuApr2021.html [Patch, Third Party Advisory]
https://www.oracle.com/security-alerts/cpujan2021.html [Patch, Third Party Advisory]
https://www.oracle.com/security-alerts/cpujul2020.html [Third Party Advisory]
https://www.oracle.com/security-alerts/cpuoct2020.html [Patch, Third Party Advisory]
https://www.oracle.com/security-alerts/cpuoct2021.html [Patch, Third Party Advisory]
https://www.synology.com/security/advisory/Synology_SA_20_05 [Third Party Advisory]
https://www.synology.com/security/advisory/Synology_SA_20_05_OpenSSL [Third Party Advisory]
https://www.tenable.com/security/tns-2020-03 [Third Party Advisory]
https://www.tenable.com/security/tns-2020-04 [Third Party Advisory]
https://www.tenable.com/security/tns-2020-11 [Third Party Advisory]
https://www.tenable.com/security/tns-2021-10 [Third Party Advisory]

Authoritative record: CVE-2020-1967 at cve.org

Vendors: openssl

Weaknesses: CWE-476

About this page

This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2020-1967 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Monday, October 19, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.